Inherited Breast Cancer

Breast cancer is a common disease. The American Cancer Society says there will be over 180,000 new cases of breast cancer in the United States this year. More than 40,000 may die from breast cancer this year.

Individual risks may vary depending on factors such as age, family history, reproductive history, and race/ethnicity.

A small number of breast cancer cases (5-10%) are caused by an inherited mutation in tumor suppressor genes. These are specific genes which may be linked to breast cancer and ovarian cancer. Each parent with a cancer-causing mutation has a 50% (1 in 2) chance of passing the mutation on to each child. This is because only one of each parent's chromosomes is passed on to the child during reproduction.

There are specific genes which may be linked to breast cancer and ovarian cancer. These are called tumor suppressor genes. A small number of breast cancer cases (5-10%) are caused by an inherited mutation in a tumor suppressor gene. The rest are sporadic cancers and are not due to an inherited mutation.

Even if more than one relative has breast cancer, it does not mean it is due to an inherited mutation. The other 90-95% breast cancer cases are sporadic cancers and are not due to an inherited mutation. In general, women who do not have a mutation have about a 1 in 8 chance (12.5%) of being diagnosed with breast cancer at some point in their lives.